It has been known for many years to employ rotating flails for clearing terrain sown with land mines, as is shown by U.S. Pat. No. 2,496,423. Such known mine clearance systems comprise a single rigid flail axle (or drum) carried on a pair of side arms in front of a propelling vehicle, which is commonly a tank. A number of flail chains are attached to the flail axle at points along the axle, so as to form a flail system in which the flail chains beat the terrain when the flail axle is rotated. As the vehicle moves forward carrying the rotating flail system in front of it, a strip of terrain is more or less cleared of mines due to their being detonated by chain impact. In order to avoid the vehicle passing over uncleared terrain at the margins of the cleared strip, the flail system is necessarily at least as wide as the vehicle, and the flail system is normally wider than the vehicle both to preserve the vehicle and to maximize the area of cleared terrain. The flail-mounting side arms effectively increase the gross width of the terrain clearance system since they must necessarily be located at either end of the flail axle to avoid collision with the flail chains. Thus known flail systems inevitably have an overall width in excess of the overall width of the propelling vehicle.
The flail-mounting side arms are commonly pivoted at their points of attachment to the propelling vehicle such that the flail system can rise or fall as a whole about a pivot axis which is horizontal when the propelling vehicle is upright and which is also at right angles to the straight-ahead direction of vehicle travel. However, even if the side arms are fully raised to lift the flail system clear of the terrain (for example, if the vehicle is crossing mine-free terrain), the known flail systems impose an irreducible transverse clearance requirement in excess of that due to the width of the vehicle alone. This excess width requirement for terrain clearance vehicles when not employed on terrain clearance duties is a disadvantage since, for example, an otherwise suitable vehicle may be prevented from using facilities such as tracks, highways, gates, bridges, garages, and workshops (or else these facilities must provide clearance which is wider than is necessary for the vehicle alone).
It is therefore an object of the invention to provide a terrain clearance system and a flail system therefor in which the above-described disadvantage is obviated or mitigated.